The narrow market definition is self-referential because Apple controls both the hardware and software. You could say "Apple A4/A5 compatible", but is that really any different? "Intel-compatible" is a meaningful term, since many vendors provide x86 hardware to consumers. How many vendors provide Apple A4/A5 hardware to consumers? The arbitrary market that was defined in the Microsoft case was my biggest problem with the case. They did not define the market as "desktop computers". That would have had too many viable competitors. They narrowed the market to where they believed there were no viable competitors. If the market had been "desktop computers", then Microsoft could have displayed a variety of Mac users that used their operating systems, entertainment programs, business productivity suites, and other applications using systems that were easily available to everyone. That would have damaged the case, so they drew the market more narrowly.
You are correct that Toshiba has a monopoly on "Toshiba laptops", if you draw the market that narrowly. But Toshiba produces the hardware, not the software. The software runs on a variety of "compatible" laptops. You can buy a laptop from HP and install the exact same software on it as you would on the Toshiba. Toshiba does not prevent you from doing that. This exact situation happened a few years ago when my girlfriend started going to college. I had an HP laptop they she used occasionally for games, or typing up letters and resumes, or surfing the web, etc. When she started classes, we went to Best Buy and she picked out a Toshiba Satellite. After we brought it home, I installed software and set it up so that she had exactly the same things on the Toshiba that she had on the HP (from a software perspective). Can I do the same thing with iPad/iOS? Can I buy an iPad and easily run Android? Can I buy a Samsung Galaxy Tab 10.1 (certainly not down under) and easily run iOS? I can't do that because Apple ties the products together.
And now we have everyone's favorite; a car analogy! Yes, Goodyear does, in fact, have a monopoly on "Goodyear tires". But not on "passenger vehicle tires", or on "P225/60R16 tires". I can buy my vehicle with Goodyear tires and easily replace those with Bridgestone tires. Or have Goodyear on the front and Michelin on the rear. There are many brands within the tire market, because the companies build to a standard specification. If Goodyear bought Toyota and produced a proprietary tire that only worked on Toyotas, and Toyotas could only use those tires, that would be seen as creating a barrier to participation in the tire market for other tire vendors. They would no longer be participating in a broader "passenger vehicle tire" market, they would have drawn a narrower market and monopolized it.
Last week I took my girlfriend to see "Dr. Horrible's Sing Along Blog Live", performed by a local theater company. She had never seen "Dr. Horrible", so I went to download it on my Xoom so she could watch it. I, of course, could not install iTunes on my Xoom and could not purchase anything from the iTunes store without having iTunes installed. So I went to my Windows machine, installed iTunes, and purchased the HD version. Which I cannot watch on my Xoom. I could watch it on an iPad, but not on a Xoom.
I am not trying to excuse Microsoft at all. I have no vested interest in Microsoft. I am not a stockholder. Like many other companies, Microsoft has engaged in abusive and anti-competitive behavior. I'm just pointing out what I believe to be serious hypocrisy. Microsoft was never able to exert the level of control that Apple does. But Microsoft was taken to court, and initially ordered to be split up, for the same behavior as other companies. If it's good for the goose, it's good for the gander. If we're going to say that you can't tie products together, then damnit you shouldn't be allowed to tie products together. I believe in the separation between the hardware market and the software market. I believe that separation creates a more competitive market that benefits the consumers.
You know what people ask me when they see my Xoom? "Is that an iPad?" When I say that, no, it's a Xoom, it's an Android they say "Oh, so it's like an iPad." Ancecdotal, certainly, but I believe that it represents a very popular perspective. The same thing happened with portable music devices and the iPod. The popularity of the iPod, and then iTunes, and then the iPad demonstrates a very strong tie between Apple products. Having a popular product, or even having the only product, is not wrong or illegal. Leveraging that popularity into control is wrong, even if it's not illegal.
Apple has a large market share. Apple leverages that share to disadvantage competitors. Apple does not need anything else to be the "new Microsoft". They've been worse than Microsoft for a long time.